1. Field of the Invention
The present invention relates to an information storage medium having user data areas and additional data areas and a method of reproducing information recorded on the information storage medium, and more particularly, to an information storage medium having an improved structure in which user data areas are distinguished from additional data areas and a method of recording information thereon and/or reproducing information from the information storage medium.
2. Description of the Related Art
Optical discs are generally used as information storage media of optical pickup devices which record information on and/or reproduce information from the optical discs without contacting the optical discs. Optical discs are classified as either compact discs (CDs) or digital versatile discs (DVDs) according to their information recording capacity. Optical discs can also be classified as either recordable discs or read-only discs according to their recording potential. Here, the recordable discs include 650 MB CD-Rs, CD-RWs, 4.7 GB DVD+R/RWs, DVD-random access memories (DVD-RAMs), DVD-R/RWs, and so forth. The read-only discs include 650 MB CDs, 4.7 GB DVD-ROMs, and the like.
FIG. 1 illustrates the data structure of a recordable information storage medium such as a CD-R or a CD-RW. Referring to FIG. 1, the recordable information storage medium includes user data areas A and additional data areas B located before and after the user data areas A. Here, the user data areas A are physical clusters in which data is recorded. The additional data areas B are divided into run-in areas and run-out areas.
The additional data areas B serve as spare areas in which data can be recorded even when a recording position of the information storage medium is changed with a variation in the speed of a spindle motor during rotating of the information storage medium on a turntable.
In a case where a read-only information storage medium is manufactured according to the above-described format, the read-only information storage medium is required to have the same structure as the recordable information storage medium so as to have reproduction compatibility in a drive and a format consistent with the recordable information storage medium. In other words, the read-only information storage medium has a structure including user data areas A and additional data areas B. Here, the additional data areas B are located before and after the user data areas A and must have the same length as the run-in areas and the run-out areas described with reference to FIG. 1. In this case, the additional data areas B have to be separated from the user data areas A.